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v3.21.1

Basis of presentation - Narrative (Details) | 12 Months Ended |  |
--- | --- | --- | ---
Dec. 31, 2020 USD ($) method branch | Dec. 31, 2019 USD ($) branch | Dec. 31, 2018 USD ($) | Jan. 01, 2020 USD ($) | Dec. 31, 2017 USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Number of full-service branches | branch | 81 |  |  |  |
Provision for credit losses on available-for-sale securities | $ 0 |  |  |  |
Transfer from loans held for sale to loan portfolio | 55,766,000 | $ 12,259,000 | $ 14,732,000 |  |
Transfer of from loan portfolio to held for sale | $ 11,483,000 | 7,891,000 | 11,888,000 |  |
Adjustments for transfers to loans HFS |  |  | 349,000 |  |
Percent of remaining principal allowed to buy back under GNMA optional repurchase programs | 100.00% |  |  |  |
Lessee, number of finance leases | branch | 1 |  |  |  |
Cumulative effect adjustment of adoption of accounting principle | $ (1,291,382,000) | (762,329,000) | (671,857,000) |  |
Goodwill impairment | 0 | 0 |  |  |
Amounts related to uncertain tax positions | 0 | 0 | 0 |  |
Impairment of long-lived assets | $ 0 | 0 |  |  |
Number of methods to deliver mortgage loans | method | 2 |  |  |  |
Deposits with Federal Home Loan Banks | $ 12,729,000 | 11,225,000 |  |  |
FHLB lender risk account guaranty | $ 6,183,000 | 5,546,000 |  |  |
Lender risk account, contribution percentage | 1 |  |  |  |
Lender risk account, period to release portion of funds not used to cover losses | 30 years |  |  |  |
Lender risk account, initial fill-up period | 5 years |  |  |  |
Loans | $ 7,082,959,000 | $ 4,409,642,000 | 3,667,511,000 | $ 4,409,642,000 |
Residential mortgage |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Transfer of from loan portfolio to held for sale | $ 2,116,000 |  |  |  |
PSUs |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Criteria period | 3 years |  |  |  |
Franklin Financial Network, Inc. |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Lessee, number of finance leases | branch | 1 | 0 |  |  |
Mortgage Loans |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Net gains (losses) from fair value changes of mortgage loans | $ 24,233,000 | $ (2,861,000) | (4,539,000) |  |
GNMA |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Transfer of from loan portfolio to held for sale | 9,367,000 | 7,891,000 | 0 |  |
Delinquent GNMA loans that had been previously sold | 151,184,000 | 51,705,000 |  |  |
Residential Mortgage Loans |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Transfer from loans held for sale to loan portfolio | 55,766,000 | 12,259,000 | 14,732,000 |  |
FHLB Cincinnati |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Deposits with Federal Home Loan Banks | $ 12,729,000 | 11,225,000 |  |  |
Leasehold improvements | Maximum |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Property, plant and equipment, useful life | 20 years |  |  |  |
Premises |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Property, plant and equipment, useful life | 40 years |  |  |  |
Furniture and fixtures | Minimum |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Property, plant and equipment, useful life | 7 years |  |  |  |
Furniture and fixtures | Maximum |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Property, plant and equipment, useful life | 10 years |  |  |  |
Equipment | Minimum |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Property, plant and equipment, useful life | 3 years |  |  |  |
Equipment | Maximum |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Property, plant and equipment, useful life | 7 years |  |  |  |
Retained earnings |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Cumulative effect adjustment of adoption of accounting principle | $ (317,625,000) | (293,524,000) | (221,213,000) |  |
Cumulative effect of change in accounting principle |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Cumulative effect adjustment of adoption of accounting principle |  | $ 25,018,000 | 1,309,000 |  | $ 0
Loans |  |  |  | 558,000 |
Cumulative effect of change in accounting principle | Retained earnings |  |  |  |  |
New Accounting Pronouncements or Change in Accounting Principle [Line Items] |  |  |  |  |
Cumulative effect adjustment of adoption of accounting principle |  |  | $ 1,309,000 | $ 25,018,000 | $ 109,000

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